Reporting on part of the data collected in the Junior High Classroom Organization Study, this document focuses on the mathematics subsample. Twenty-six mathematics teachers in 11 junior high schools were observed in two classes. The major purpose of this paper is to describe the classroom procedures and behaviors of teachers identified as effective classroom managers. First, the correlations of management variables and the achievement and attitude variables are considered. Next the extent to which teachers affect the classes' achievement gains is reviewed, followed by a description of the process of selecting subsamples for further analysis and description. A model of appropriate and inappropriate teacher management methods is outlined, and further illustrated by two case studies excerpted from narrative scripts that describe a poor manager and a highly capable one. The study indicates that effective classroom management throughout the year is facilitated by several facets. Among these, the good manager made a clear set of expectations for appropriate student behavior in a wide variety of class activities, and were characterized by good monitoring and prompt handling of inappropriate behavior. (MP)